A method for analyzing crack permeation deformation of a seepage prevention system

Abstract

A method for analyzing the seepage deformation of cracks in a seepage prevention system belongs to the technical field of numerical analysis methods in geotechnical engineering. It includes: First, establishing a mesh model and a seepage calculation model based on a discrete crack model; second, obtaining the pressure head and hydraulic gradient distribution results from the seepage calculation model, converting them into seepage water pressure loads and seepage volume force loads, and transferring them to a finite element stress-deformation solver to obtain the crack changes in the earth-rock dam; third, evaluating the dam's condition, dynamically updating the dam's porosity, and correcting the seepage coefficient of the seepage prevention system cracks; re-invoking the finite volume seepage solver to obtain the changes in pressure head and displacement; finally, determining whether the convergence criteria have been met to obtain the final result. This invention overcomes the limitations of insufficient accuracy in traditional single-field simulations and the difficulty of continuous medium models in depicting concentrated seepage channels, achieving refined simulation of the entire process of seepage deformation in a seepage prevention system, from crack initiation to expansion.

Description

Technical Field

[0001] This invention belongs to the technical field of numerical analysis methods in geotechnical engineering, and relates to a method for analyzing the seepage deformation of cracks in a seepage prevention system, particularly a method for analyzing the seepage deformation of cracks in a seepage prevention system based on a finite volume-finite element coupled framework and a discrete crack model. Background Technology

[0002] In recent years, research on the soil-water coupling mechanism under extreme environments has become an important frontier topic in geotechnical engineering. In engineering practice, typical engineering problems such as deep overburden erosion, tunnel water inrush disasters, underground cavern erosion and damage, landslide-debris flow geological hazards, and seepage deformation and instability of earth-rock dams all highlight the complexity and hazards of seepage-stress coupling. These engineering problems not only directly endanger the safe operation of major infrastructure, but the secondary disasters they trigger can also lead to severe economic losses and far-reaching social impacts.

[0003] A deeper analysis of these engineering problems reveals that their essential characteristic lies in the dynamic coupling effect between the seepage field and the stress field: on the one hand, seepage alters the effective stress state of the soil and rock mass, inducing structural deformation or even instability; on the other hand, under extreme conditions such as sudden temperature changes, uneven settlement, and earthquakes, seepage prevention systems (such as concrete panels and cutoff walls) often experience varying degrees of cracking damage. The formation of these cracks significantly alters the seepage field distribution, leading to an abnormal rise in the dam's phreatic line, which in turn exacerbates the seepage-stress coupling effect, creating a vicious cycle and ultimately threatening the overall safety of the project.

[0004] Therefore, conducting research on the seepage characteristics of seepage control systems under cracking conditions and establishing a coupled analysis model that can accurately reflect the seepage characteristics of cracks is of significant theoretical and practical value for ensuring the long-term safe operation of water conservancy projects. This not only helps to deepen the understanding of the interaction mechanism between seepage and stress under extreme conditions, but also provides a scientific basis for engineering seepage control design and safety assessment.

[0005] For example, Chinese invention patent 2024110199496 provides a grid-based simulation analysis method and system for the hydraulic coupling stability of earth-rock dams. It achieves stability assessment of the hydraulic coupling of earth-rock dams by constructing a network simulation model, a seepage-stress coupling model, and a local mesh refinement model. Chinese invention patent 202211082004X provides a multi-field, multi-scale numerical analysis method and system suitable for jointed rock masses. It simplifies the numerical modeling process by transforming the traditional constitutive modeling and integration process into a fine-structure simulation and homogenization analysis under periodic boundary conditions. However, existing technologies have shortcomings in characterizing the seepage-stress coupling mechanism, especially under the condition of cracking in seepage control systems. They fail to accurately depict the nonlinear dynamic response characteristics of the interaction between the seepage field and the stress field, leading to significant deviations between the calculation results and actual engineering conditions, making it difficult to truly reflect the system behavior under complex conditions.

[0006] Therefore, this invention innovatively proposes a collaborative analysis method combining a finite volume-finite element coupled framework and a discrete crack model. By establishing a dynamic coupling mechanism between crack seepage in the seepage prevention system and dam deformation, it realizes the full-process coupled simulation of seepage characteristics and deformation behavior after cracking of the seepage prevention system, providing a brand-new solution for seepage safety assessment of major water conservancy projects. Summary of the Invention

[0007] This invention addresses the engineering challenge of seepage-stress coupling in seepage control systems by innovatively proposing a method for analyzing seepage deformation in such systems. Specifically, it is a refined analysis method based on a finite volume-finite element (FVM) coupled framework and a discrete crack model. This invention employs the finite volume method (FVM) to accurately simulate the seepage process in saturated and unsaturated soil and cracks, while simultaneously using the finite element method (FEM) to accurately calculate the stress and deformation of the dam body. By establishing a dynamic coupling mechanism between the seepage field and the stress field, it overcomes the limitations of traditional single-field simulations, which lack sufficient accuracy, and the inability of continuous medium models to characterize concentrated seepage channels. This enables refined simulation of the entire seepage control system process, from crack initiation to seepage deformation. This innovative method provides a novel technical means for the safety assessment of seepage in water conservancy projects.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for analyzing the seepage deformation of cracks in a seepage prevention system, the method comprising the following steps: S1. Based on the crack situation of the seepage prevention system, a geometric model of the dam including the cracks in the seepage prevention system is established based on the discrete crack model. High-precision mesh discretization is then performed, initial permeability coefficients of the dam body and seepage prevention system cracks are set, and upstream and downstream water level boundaries are defined to obtain the mesh model and seepage calculation model. Specifically: S1.1, based on the actual engineering characteristics of cracks in earth-rock dams (panel, core wall, dam shell, dam foundation, etc.) and seepage prevention systems, geometric modeling of the distribution of cracks in the dam body and seepage prevention system is completed in the computational domain based on a discrete crack model, resulting in a dam geometric model. Unstructured mesh technology is then used to complete the spatial discretization of the computational domain to obtain a mesh model, ensuring accurate geometric representation of complex dam structures.

[0009] S1.2, based on geological surveys and similar projects, assigns corresponding initial permeability coefficients to the material zones and seepage prevention system cracks of the earth-rock dam; simultaneously, based on actual hydrological conditions, sets initial upstream and downstream water level boundary conditions to obtain a seepage calculation model. Details are as follows: The permeability coefficients of different material zones in an earth-rock dam can be preliminarily determined based on engineering experience and dam material tests. The permeability coefficients for cracks in the seepage prevention system are set considering that the actual crack width typically changes along the water flow direction, and that the surface is rough and uneven with some filling material; therefore, an equivalent crack width is adopted. and roughness correction factor C c and filling porosity The permeability coefficient of the cracks in the seepage prevention system was characterized.

[0010] For length of a Width is b The permeability coefficient of the cracks in the seepage prevention system before correction is as follows: (1) In the formula: The viscosity coefficient of the fluid. For the specific gravity of water, denoted as the crack permeability coefficient.

[0011] Considering factors such as the filling condition of the cracks in the seepage prevention system, the variation in crack width, and the unevenness of the crack surface, the corrected crack permeability coefficient is as follows: (2) (3) (4) In the formula: , These are the widths of the crack's inlet and outlet, respectively. The height of the protrusion on the surface of the crack; The relative height of the protrusion; This is the roughness correction factor; To fill the porosity; The equivalent width of the crack.

[0012] S2, based on the seepage calculation model obtained in S1, uses a three-dimensional high-performance finite volume seepage solver for numerical calculation to obtain the pressure head and hydraulic gradient distribution results. Specifically: S2.1, Based on the seepage calculation model obtained in S1, the three-dimensional high-performance finite volume seepage solver is invoked, and the head convergence accuracy is set to 1.0 × 10⁻⁶. -5 Complete the seepage calculation of the dam body.

[0013] S2.2, organize the seepage calculation results of S2.1, and obtain the pressure head and hydraulic gradient distribution results under the given initial earth-rock dam and seepage prevention system crack permeability coefficient.

[0014] S3 converts the pressure head obtained from S2 into a seepage water pressure load and the hydraulic gradient into a seepage volumetric force load, which are then transferred to the finite element stress-deformation solver. Specifically: S3.1 converts the pressure head obtained in S2 into a seepage water pressure load. p for: (5) in, Indicates the specific gravity of water; This indicates the pressure head distribution.

[0015] S3.2, convert the hydraulic gradient obtained in S2 into a seepage volume force load, which is: (6) in, This represents the volumetric force load from seepage in the x-direction; This represents the volumetric force load of seepage in the y-direction; This represents the volumetric force load of seepage in the z-direction; This represents the hydraulic gradient in the x-direction; This represents the hydraulic gradient in the y-direction; This represents the hydraulic gradient in the z-direction; Indicates the specific gravity of water; x In Cartesian coordinate system x direction; y In Cartesian coordinate system y Direction; z represents the Cartesian coordinate system. z direction; express x Directional hydraulic gradient; express y Directional hydraulic gradient; express z Directional hydraulic gradient.

[0016] S3.3 transfers the seepage water pressure load obtained in S3.1 and the seepage volume force load obtained in S3.2 to the finite element stress-deformation solver.

[0017] S4, based on the mesh model obtained in S1, sets the constitutive parameters of the earth-rock dam material. Using the seepage water pressure load and seepage volumetric force load obtained in S3 as external load conditions, the finite element stress-deformation solver is called to obtain the stress, displacement, volumetric strain, and crack changes in the seepage prevention system of the earth-rock dam. Specifically: S4.1 Based on the mesh model obtained in S1, set the constitutive model of each material zone of the earth-rock dam, assign calculation parameters, and set the parameters of the finite element stress-deformation solver; the mesh model is a three-dimensional mesh model.

[0018] S4.2 uses the seepage water pressure load and seepage volume force load obtained in S3 as external load conditions, and calls the finite element stress-deformation solver to obtain the stress, displacement, volume strain values ​​and crack width changes of the earth-rock dam.

[0019] S5 assesses the dam's condition based on the stress and displacement results obtained in S4, dynamically updates the dam's porosity based on the volumetric strain values ​​obtained in S4, and then corrects the dam's permeability coefficient based on the new porosity. Finally, it corrects the permeability coefficient of the seepage prevention system based on crack changes. Specifically: S5.1, Update the porosity of the earth-rock dam based on the strain value of the earth-rock dam body: (7) In the formula: The initial porosity, Porosity For the body to adapt to strain.

[0020] S5.2, Correct the permeability coefficient of the earth-rock dam based on the updated porosity: (8) In the formula: K s The corrected permeability coefficient for earth-rock dams; The initial absolute permeability of the earth-rock dam; The dynamic viscosity coefficient of water; The density of water; It is the acceleration due to gravity; The initial porosity, Porosity For the body to adapt to strain.

[0021] S5.3, Adjust the permeability coefficient of the seepage prevention system according to the changes in cracks: (9) In the formula: The new crack width obtained from S4.2; The viscosity coefficient of the fluid. For the specific gravity of water, The new fracture permeability coefficient; C c This is the roughness correction factor; Porosity.

[0022] In step S6, based on the corrected permeability coefficient obtained in S5, the three-dimensional high-performance finite volume seepage solver is invoked again to obtain new pressure head and hydraulic gradient distribution results. The process then returns to steps S3-S5 to complete one bidirectional coupled iterative calculation of the seepage field and stress field, obtaining the changes in pressure head and displacement. Specifically: The change in pressure head is calculated using the following formula: (10) In the formula: This represents the change in pressure head between two iteration steps; and The first m Second and m Pressure head value of +1 iteration step.

[0023] The displacement change is calculated using the following formula: (11) In the formula: This represents the displacement change between two iterations; and Representing the first m Second and m The displacement value of +1 iteration step.

[0024] S7 determines whether the pressure head change and displacement change obtained in S6 meet the convergence criteria. If they do, the seepage-stress two-way iterative coupled calculation is completed; otherwise, it returns to step S2 and restarts the calculation. Specifically: The convergence criteria for the pressure head and displacement change are shown in the following formula: (12) In the formula: This represents the convergence accuracy of the pressure head, and its value is 1.0 × 10⁻⁶. -4 ; This represents the displacement convergence accuracy, with a value of 1.0 × 10⁻⁶. -4 Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention achieves accurate characterization of the crack seepage characteristics of the seepage prevention system by introducing a discrete crack model, and accurately simulates the dominant seepage channels formed by cracks and their evolution process.

[0025] (2) This invention realizes the combined application of a three-dimensional high-performance finite volume flow solver and a finite element stress-deformation solver, providing multiple data interaction modes. All numerical tools are independently developed, the system has strong controllability, and is easy to promote and apply.

[0026] (3) This invention innovatively constructs a new analytical framework that integrates discrete crack model and finite volume-finite element coupling method, establishes a dynamic coupling mechanism between crack evolution of seepage prevention system and seepage deformation of dam body, and realizes full coupling and refined simulation of crack of seepage prevention system and seepage deformation of dam body. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the main process of the method of the present invention; Figure 2 A model diagram of panel cracks; Figure 3 This is a contour map of the pressure head when the panel is not cracked, in meters; Figure 4 This is a contour map of the pressure head after the panel cracked, in meters; Figure 5 A comparison of the wetting lines before and after the panel cracked; Figure 6 This is a contour map of the dam body's displacement along the river when the dam panel has not cracked during the full storage period, in cm. Figure 7 This is a contour map of the dam body's displacement along the river after the panel cracks during the full storage period, in cm. Figure 8 This is a contour map of the vertical settlement of the panel dam when the panel has not cracked during the full storage period, in cm. Figure 9 This is a contour map of the vertical settlement of the dam panel after cracking during the full storage period, in cm. Figure 10 This is a contour map of the dam body's displacement along the river caused by seepage, in cm. Figure 11 This is a contour map of the principal stresses when the panel has not cracked during the full storage period, with units in MPa. Figure 12 This is a contour map of the principal stresses after the panel cracks during the full storage period, with units in MPa. Figure 13 This is a contour map of minor principal stresses when the panel has not cracked during the full storage period, with units in MPa; Figure 14 This is a contour map of minor principal stresses after the panel cracks during the full storage period, with units in MPa. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0029] See Figure 1 This embodiment provides a method for analyzing the seepage deformation of cracks in a seepage prevention system. Specifically, it is a method combining an FVM-FEM coupled framework with a discrete fracture model, comprising the following steps: S1. Based on the crack situation of the seepage prevention system, a geometric model of the dam containing the cracks of the seepage prevention system is established based on the discrete crack model. High-precision mesh discretization is performed, the initial permeability coefficients of the dam body and the cracks of the seepage prevention system are set, and the upstream and downstream water level boundaries are set to obtain the mesh model and seepage calculation model.

[0030] S2, based on the seepage calculation model obtained in S1, uses a three-dimensional high-performance finite volume seepage solver for numerical calculation to obtain the pressure head and hydraulic gradient distribution results.

[0031] S3 converts the pressure head obtained from S2 into a seepage water pressure load and the hydraulic gradient into a seepage volume force load, which are then transferred to the finite element stress-deformation solver.

[0032] S4. Based on the mesh model obtained in S1, set the constitutive parameters of the earth-rock dam material, take the seepage water pressure load and seepage volume force load obtained in S3 as external load conditions, call the finite element stress-deformation solver, and obtain the results of stress, displacement, volume strain and crack changes of the seepage prevention system of the earth-rock dam.

[0033] S5 assesses the state of the earth-rock dam body based on the stress and displacement results obtained in S4, dynamically updates the porosity of the earth-rock dam body based on the volumetric strain values ​​obtained in S4, corrects the permeability coefficient of the earth-rock dam body based on the new porosity, and corrects the crack permeability coefficient of the seepage prevention system based on the crack changes.

[0034] S6, based on the corrected permeability coefficient obtained in S5, calls the three-dimensional high-performance finite volume seepage solver again to obtain new pressure head and hydraulic gradient distribution results, and returns to S3~S5 to complete a two-way coupled iterative calculation of seepage field-stress field to obtain the pressure head change and displacement change.

[0035] S7. Determine whether the pressure head change and displacement change obtained in S6 meet the convergence criteria. If they meet the convergence criteria, complete the seepage-stress bidirectional iterative coupling calculation. If they do not meet the convergence criteria, return to step S2 and start the calculation again.

[0036] To demonstrate the effectiveness of this technical solution, a numerical simulation is conducted on the seepage deformation problem of a concrete panel dam with cracks (Example 1).

[0037] Example 1: Problem of seepage deformation and cracking in the concrete panel of a dam: S1. Based on the crack situation of the seepage prevention system, a geometric model of the dam containing the cracks of the seepage prevention system is established based on the discrete crack model. High-precision mesh discretization is performed, the initial permeability coefficients of the dam body and the cracks of the seepage prevention system are set, and the upstream and downstream water level boundaries are set to obtain the mesh model and seepage calculation model.

[0038] S1.1, based on the actual engineering characteristics of cracks in earth-rock dams (panel, core wall, dam shell, dam foundation, etc.) and seepage prevention systems, geometric modeling of the distribution of cracks in the dam body and seepage prevention system is completed in the computational domain based on a discrete crack model, resulting in a dam geometric model. Unstructured mesh technology is then used to complete the spatial discretization of the computational domain to obtain a mesh model, ensuring accurate geometric representation of complex dam structures.

[0039] refer to Figure 2 A two-dimensional concrete-faced rockfill dam model was established. The model has a dam height of 56.0m, a dam width of 8.0m, and a dam crest length of 450.65m. The upstream and downstream slope ratios are 1:1.4 and 1:1.67, respectively. The simulated working condition is the reservoir full storage period, at which the upstream water level is 175.4m and the downstream water level is 126.0m. Ten through cracks are pre-set on the panel.

[0040] S1.2, Based on geological surveys and similar projects, assign corresponding initial permeability coefficients to the material zones and seepage prevention system cracks of the earth-rock dam; at the same time, based on actual hydrological conditions, set initial upstream and downstream water level boundary conditions to obtain a seepage calculation model. The information on panel cracks is shown in Table 1. Tables 2 and 3 show the permeability coefficients of the main materials of the dam body and the unsaturated characteristic parameters of the dam body materials.

[0041] Table 1: Panel Crack Parameter Table

[0042] Table 2: Permeability Coefficients of Main Materials by Zone

[0043] Table 3: Unsaturated property parameters of dam body materials

[0044] S2, based on the seepage calculation model obtained in S1, uses a three-dimensional high-performance finite volume seepage solver for numerical calculation to obtain the pressure head and hydraulic gradient distribution results.

[0045] S2.1, Based on the seepage calculation model obtained in S1, the three-dimensional high-performance finite volume seepage solver is invoked, and the head convergence accuracy is set to 1.0 × 10⁻⁶. -5 Complete the seepage calculation of the dam body; S2.2, organize the seepage calculation results of S2.1, and obtain the pressure head and hydraulic gradient distribution results under the given initial earth-rock dam and seepage prevention system crack permeability coefficient.

[0046] Figure 3 This is a contour map of the pressure head of the panel without cracks. Figure 4 This is a contour map of the pressure head after the panel cracked. Figure 5 A comparison of the wetting lines before and after the panel cracked; S3 converts the pressure head obtained from S2 into a seepage water pressure load and the hydraulic gradient into a seepage volumetric force load, which are then transferred to the finite element stress-deformation solver. Specifically: S3.1, convert the pressure head obtained from S2 into a seepage water pressure load, which is obtained by formula (5).

[0047] S3.2, convert the hydraulic gradient obtained in S2 into a seepage volume force load, which is obtained by formula (6).

[0048] S3.3, transfer the seepage water pressure load obtained in S3.1 and the seepage volume force load obtained in S3.2 to the finite element stress-deformation solver; S4. Based on the mesh model obtained in S1, set the constitutive parameters of the earth-rock dam material, take the seepage water pressure load and seepage volume force load obtained in S3 as external load conditions, call the finite element stress-deformation solver, and obtain the results of stress, displacement, volume strain and crack changes of the seepage prevention system of the earth-rock dam.

[0049] In this embodiment, an elastoplastic damage constitutive model is used for the concrete panel, a generalized plastic constitutive model is used for the dam body rockfill, and a simplified linear elastic model is used for the foundation system. Furthermore, the contact behavior between the panel and the cushion layer is modeled using the generalized plastic contact surface model proposed by Zou Degao's team. The selection of these stress models effectively reflects the stress and deformation of the dam body. Specific stress calculation parameters are shown in Tables 4 to 8.

[0050] Table 4: Parameters of the Generalized Plastic Model of the Dam (Subbase Material)

[0051] Table 5: Parameters of the Generalized Plastic Model of the Dam (Transition Material)

[0052] Table 6: Parameters of the Generalized Plastic Model of the Dam (Rockfill)

[0053] Table 7: Parameters of the Generalized Plastic Model of the Contact Surface

[0054] Table 8: Static damage parameters of concrete panels

[0055] Figure 6 This is a contour map of the dam body's displacement along the river when the dam panel has not cracked during the full storage period; Figure 7 Contour map of the dam body's displacement along the river after the panel cracks during the full storage period; Figure 8 This is a contour map of vertical settlement of the panel dam when the panel has not cracked during the full storage period; Figure 9 Contour map of vertical settlement of the dam panel after cracking of the panel during the full storage period; Figure 10 Contour map of the dam body's displacement along the river caused by seepage; Figure 11 This is a contour map of the principal stresses when the panel has not cracked during the full storage period. Figure 12 This is a contour map of the principal stresses after the panel cracks during the full storage period. Figure 13 This is a contour map of minor principal stresses when the panel has not cracked during the full storage period. Figure 14 This is a contour map of minor principal stresses after the panel cracks during the full storage period.

[0056] S5 assesses the state of the earth-rock dam body based on the stress and displacement results obtained in S4, dynamically updates the porosity of the earth-rock dam body based on the volumetric strain values ​​obtained in S4, corrects the permeability coefficient of the earth-rock dam body based on the new porosity, and corrects the crack permeability coefficient of the seepage prevention system based on the crack changes.

[0057] S5.1, The porosity of the earth-rock dam is updated based on the strain value of the earth-rock dam body and obtained by formula (7).

[0058] S5.2, the permeability coefficient of the earth-rock dam is obtained by correcting the porosity of the earth-rock dam according to the updated porosity, and is obtained by formula (8).

[0059] S5.3, the permeability coefficient of the seepage prevention system is corrected according to the changes in cracks and obtained by formula (9).

[0060] S6, based on the corrected permeability coefficient obtained in S5, the three-dimensional high-performance finite volume seepage solver is called again to obtain the new pressure head and hydraulic gradient distribution results, and returns to S3~S5 to complete a two-way coupled iterative calculation of seepage field-stress field, and obtains the pressure head change and displacement change based on formula (10) and formula (11).

[0061] S7 determines whether the pressure head change and displacement change obtained in S6 meet the convergence criteria. If they do, the seepage-stress two-way iterative coupled calculation is completed; otherwise, it returns to step S2 and restarts the calculation. Specifically: The convergence criteria for the changes in pressure head and displacement are shown in the following formula: (12) In the formula: The convergence criterion representing the change in pressure head is taken as 1.0 × 10⁻⁶. -4 ; The convergence criterion representing the change in displacement is set to 1.0 × 10⁻⁶. -4 .

[0062] Based on the results of this invention, it can be seen that before the concrete panel cracked, the height of the saturation line was 127.30m and the height of the overflow point was 127.00m; after the concrete panel cracked, the height of the saturation line rose to 141.20m, an increase of 13.9m, and the height of the overflow point also increased to 129.00m, an increase of 2m. Figure 3 A comparison chart of pressure head distribution before cracking of concrete panels is provided. Figure 4 A comparison diagram of the pressure head distribution after cracking of the concrete panel is provided. Figure 5 A comparison diagram of the wetting line locations is provided.

[0063] Table 9 shows the maximum values ​​of stress and deformation distribution in the dam body before and after the panel cracks and seepage occurs. Figures 6-9 A comparison of dam deformation distribution is presented. Analysis shows that during the full reservoir period, the maximum downstream displacement of the dam body is 0.8 cm (upstream) and 1.8 cm (downstream); the maximum vertical settlement is 19.0 cm (approximately 0.34% of the dam height), located near about one-third of the dam height in the rockfill area. However, when the dam panel cracks and upstream reservoir water seeps into the dam body, the dam displacement field changes. Specifically, the downstream displacement of the dam body no longer shifts upstream but is generally biased downstream, with a maximum displacement of 3.4 cm, an increase of 89% compared to the full reservoir period; the vertical displacement, under the combined influence of seepage force and buoyancy force, decreases from 19 cm during the full reservoir period to 12 cm, a reduction of 37%. This indicates that the dam body exhibits a trend of downstream displacement and upward lifting under seepage. Figure 10 As can be seen, the maximum displacement along the river caused solely by seepage is 2.3 cm, which occurs at the top of the dam.

[0064] Figures 11-14A comparison of stress distribution in the dam body is presented. Analysis shows that during the full storage period, the maximum value of the major principal stress in the dam body is 1.1 MPa, and the maximum value of the minor principal stress is 0.46 MPa, both occurring in the middle of the dam bottom. After the panel cracks, under the action of seepage force and buoyancy force, the major principal stress of the dam body decreases from 1.1 MPa to 1.0 MPa, a decrease of 9%; the minor principal stress decreases from 0.46 MPa to 0.44 MPa, a decrease of 4%.

[0065] Table 9: Comparison of Extreme Values ​​of Stress and Deformation in Dam Body

[0066] Note: Downstream displacement along the river is positive; upward vertical displacement is positive.

[0067] The results show that after the dam face cracked and infiltrated, the displacement and stress field distributions of the dam body changed, mainly manifested in changes in the direction and amplitude of displacement along the river and adjustments in stress distribution. These changes reflect the significant impact of seepage on the deformation and stress state of the dam body.

[0068] The above embodiments are merely illustrative of the implementation methods of the present invention, but should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A method for analyzing crack permeation deformation of a diaphragm system, characterized by, The method for analyzing crack seepage deformation in the seepage prevention system Includes the following steps: S1. Based on the crack situation of the seepage prevention system, a geometric model of the dam containing the crack of the seepage prevention system is established based on the discrete crack model, and high-precision mesh discretization is performed. The initial permeability coefficient of the dam body and the crack of the seepage prevention system is set, and the upstream and downstream water level boundaries are set to obtain the mesh model and seepage calculation model. S2, based on the seepage calculation model obtained in S1, numerical calculations are performed using a three-dimensional high-performance finite volume seepage solver to obtain the pressure head and hydraulic gradient distribution results. S3 converts the pressure head obtained from S2 into a seepage pressure load and the hydraulic gradient into a seepage volume force load, and then transfers them to the finite element stress-deformation solver. S4. Based on the mesh model obtained in S1, set the constitutive parameters of the earth-rock dam material, take the seepage water pressure load and seepage volume force load obtained in S3 as external load conditions, call the finite element stress-deformation solver, and obtain the results of stress, displacement, volume strain and crack changes of the seepage prevention system of the earth-rock dam. S5 assesses the state of the earth-rock dam body based on the stress and displacement results obtained in S4, dynamically updates the porosity of the earth-rock dam body based on the volumetric strain value obtained in S4, corrects the permeability coefficient of the earth-rock dam body based on the new porosity, and corrects the crack permeability coefficient of the seepage prevention system based on the crack changes. S6. Based on the corrected permeability coefficient obtained in S5, the three-dimensional high-performance finite volume seepage solver is called again to obtain new pressure head and hydraulic gradient distribution results. Then, return to S3~S5 to complete a two-way coupled iterative calculation of seepage field-stress field and obtain the pressure head change and displacement change. S7. Determine whether the pressure head change and displacement change obtained in S6 meet the convergence criteria. If they meet the convergence criteria, complete the seepage-stress bidirectional iterative coupling calculation. If they do not meet the convergence criteria, return to step S2 and start the calculation again.

2. The method of analyzing crack permeation deformation of a diaphragm system according to claim 1, wherein Specifically, S1 refers to: S1.1 Based on the actual engineering characteristics of cracks in earth-rock dams and seepage prevention systems, geometric modeling of the distribution of cracks in the dam body and seepage prevention system is completed in the computational domain based on a discrete crack model to obtain the dam geometric model. Unstructured mesh technology is then used to complete the spatial discretization of the computational domain to obtain a mesh model. S1.2, based on geological surveys and similar projects, assign corresponding initial permeability coefficients to the material zones and seepage prevention system cracks of the earth-rock dam; simultaneously, based on actual hydrological conditions, set initial upstream and downstream water level boundary conditions to obtain a seepage calculation model; specifically as follows: The preliminary determination of the permeability coefficient of each material partition of the earth-rock dam is based on engineering experience and dam material test, the permeability coefficient of the crack of the anti-seepage system is set considering that the actual crack usually changes in width along the water flow direction, and the surface is rough, and there is filling material, and the equivalent crack width and the roughness correction coefficient C c , and the filling porosity characterize the permeability coefficient of the crack of the anti-seepage system; For a crack in an impervious system of length a and width b , the crack permeability coefficient before correction is as follows: （1） wherein: is the fluid viscosity, is the water bulk density, is the fracture permeability; Considering factors such as the filling condition of the cracks in the seepage prevention system, the variation in crack width, and the unevenness of the crack surface, the corrected crack permeability coefficient is as follows: （2） （3） （4） wherein: , are the inlet and outlet width of the fracture, respectively; is the asperity height of the fracture surface; is the relative asperity height; is the roughness correction factor; is the fill porosity; is the equivalent width of the fracture.

3. A method of analyzing crack permeation deformation of a diaphragm system according to claim 2, wherein Specifically, S2 is: S2.1, according to the seepage calculation model obtained in S1, calling a three-dimensional high-performance finite volume seepage solver, setting the water head convergence precision to 1.0×10 -5 , completing the dam body seepage calculation; S2.2, organize the seepage calculation results of S2.1, and obtain the pressure head and hydraulic gradient distribution results under the given initial earth-rock dam and seepage prevention system crack permeability coefficient.

4. The method for analyzing crack permeability deformation in a seepage prevention system according to claim 3, characterized in that, Specifically, S3 is: S3.1 converts the pressure head obtained in S2 into a seepage water pressure load. p for: （5） in, Indicates the specific gravity of water; Indicates the pressure head distribution; S3.2, convert the hydraulic gradient obtained in S2 into a seepage volume force load, which is: （6） in, This represents the volumetric force load from seepage in the x-direction; This represents the volumetric force load of seepage in the y-direction; This represents the volumetric force load of seepage in the z-direction; This represents the hydraulic gradient in the x-direction; This represents the hydraulic gradient in the y-direction; This represents the hydraulic gradient in the z-direction; Indicates the specific gravity of water; x In Cartesian coordinate system x direction; y In Cartesian coordinate system y Direction; z represents the Cartesian coordinate system. z direction; express x Directional hydraulic gradient; express y Directional hydraulic gradient; express z Directional hydraulic gradient; S3.3 transfers the seepage water pressure load obtained in S3.1 and the seepage volume force load obtained in S3.2 to the finite element stress-deformation solver.

5. The method for analyzing crack permeability deformation in a seepage prevention system according to claim 4, characterized in that, Specifically, S4 is: S4.1 Based on the mesh model obtained in S1, set the constitutive model for each material zone of the earth-rock dam, assign calculation parameters, and set the parameters of the finite element stress-deformation solver; the mesh model is a three-dimensional mesh model. S4.2 uses the seepage water pressure load and seepage volume force load obtained in S3 as external load conditions, and calls the finite element stress-deformation solver to obtain the stress, displacement, volume strain values ​​and crack width changes of the earth-rock dam.

6. The method for analyzing crack permeability deformation in a seepage prevention system according to claim 5, characterized in that, Specifically, S5 is: S5.1, Update the porosity of the earth-rock dam based on the strain value of the earth-rock dam body: （7） In the formula: The initial porosity, Porosity For the body strain; S5.2, Correct the permeability coefficient of the earth-rock dam based on the updated porosity: （8） In the formula: K s The corrected permeability coefficient for earth-rock dams; The initial absolute permeability of the earth-rock dam; The dynamic viscosity coefficient of water; The density of water; It is the acceleration due to gravity; The initial porosity, Porosity For the body strain; S5.3, Adjust the permeability coefficient of the seepage prevention system according to the changes in cracks: （9） In the formula: The new crack width obtained from S4.2; The viscosity coefficient of the fluid. For the specific gravity of water, The new fracture permeability coefficient; C c This is the roughness correction factor; Porosity.

7. The method for analyzing crack permeability deformation in a seepage prevention system according to claim 6, characterized in that, Specifically, S6 is: The change in pressure head is calculated using the following formula: （10） In the formula: This represents the change in pressure head between two iteration steps; and The first m Second and m Pressure head value of +1 iteration step; The displacement change is calculated using the following formula: （11） In the formula: This represents the displacement change between two iterations; and Representing the first m Second and m The displacement value of +1 iteration step.

8. The method for analyzing crack permeability deformation in a seepage prevention system according to claim 7, characterized in that, Specifically, S7 refers to: The convergence criteria for the pressure head and displacement change are shown in the following formula: （12） In the formula: This represents the convergence accuracy of the pressure head, and its value is 1.0 × 10⁻⁶. -4 ; This represents the accuracy of displacement convergence.

9. The method for analyzing crack permeability deformation in a seepage prevention system according to claim 8, characterized in that, The displacement convergence precision is 1.0x10 -4 .

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